A heap-based buffer overflow occurs in raptor_new_term_from_counted_literal() of the Raptor RDF Syntax Library between versions 2.0.15 and 2.0.16 when the language tag length is truncated to an unsigned char. If a malicious user supplies Turtle, TriG, N-Triples, or N-Quads documents containing a language tag of 256 bytes or more, the library writes beyond the allocated buffer, corrupting heap memory. This corruption can lead to application crashes and, in some circumstances, execution of arbitrary code.

The vulnerability affects all installations of the Raptor RDF Syntax Library that use the 2.0.15 or 2.0.16 releases. Any application that uses these library versions to parse RDF content – such as web services, data ingestion pipelines, or semantic analytics tools – is at risk when processing language tags longer than 255 characters.

The CVSS score of 7.1 indicates high severity, and the EPSS score of less than 1% suggests exploitation probability is currently low. The vulnerability is not listed in CISA’s KEV catalog, implying no widespread exploitation is known. However, an attacker who can supply crafted RDF documents to the library, either remotely or locally, could trigger the overflow, causing crashes or potentially gaining code execution depending on the environment and exploit chain.